Hooke's Law & Spring Constants (k)
Obj: Determine relationship between Force and Distance (x) for a spring, 
and the Force Constant (k) of a Spring.
Materials:  spring, four slotted masses, meter stick, unknown mass, “big” spring

Methods
1.  Sketch the set up.
2.  Record the “rest” position of the spring (let x_o = 0.0 cm). 
3.  Add a 50, or 100 g mass to extend the spring beyond its rest position (x_o); record the mass, and the Δx.
4.  Repeat for 3 more masses, adding the total of the masses and total Δx.
5.  Move to another station with a different spring and repeat the procedure.

Analysis
1.  For each spring, plot a graph of Force (N) vs. distance (Δx).  Let g = 10 m/s² when converting the masses to Newtons.
2.  Determine the slope (k) of the line.  What are the units and what does the slope represent?
3.  Calculate the energy in Joules for one of your springs at the various Δx’s.  Plot this energy on the same graph by using a double scale as described.
4.  Compare your force constants and draw a conclusion about the magnitude of the force constant k and the "stretchability" of a spring.
5.  Write an equation relating Force (F), displacement (Δx), and the force constant of a spring (k).  State Hooke's  Law in a sentence.
6.  Calculate the spring constant of the “big” spring, if available.
7.  Describe the mathematical relationship of the PE_s in a spring to its stretch.

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